Inherited genomic variability is one of the major causes of inter-individual variability in drug response. Even for those genes and drugs for which there is clearly clinical utility to use genetic testing as one tool to improve prescribing, use of pharmacogenetic testing in the clinic has not been rapidly adopted. The goal of the Clinical Pharmacogenetics Implementation Consortium (CPIC) is to accelerate proper use of pharmacogenomic tests in the clinic. CPIC was formed in late 2009 as a shared project between PharmGKB and NIH's Pharmacogenomics Research Network (PGRN). CPIC addresses what has been one of the major barriers to clinical implementation of pharmacogenetic tests: the lack of freely available, peer-reviewed, updatable, and detailed gene/drug clinical practice guidelines. CPIC guidelines enable the translation of genetic laboratory test results into actionable prescribing decisions for specific drugs, centering on genes or drugs. Priority is given to gene/drug groupings for which the evidence for actionable prescribing is strongest. Following peer-review, CPIC guidelines are simultaneously published in a leading journal and posted to PharmGKB. A key assumption underlying CPIC guidelines is that as clinical genomic testing expands, clinicians are faced with uncertainty about how to use genetic test results, even if they have not explicitly ordered a test for a specific drug. Thus, CPIC guidelines help clinicians understand how to use available genetic test results to guide prescribing and do not focus on whether to order genetic tests. Each CPIC guideline adheres to a standard format that includes which variants define alleles, assignment of function to alleles, translation of diplotypes into phenotypes, prescribing recommendations (graded according to strength), graded evidence to support prescribing recommendations, allele frequencies world-wide, and algorithms and example language for clinical decision support. As of August 2014, CPIC has published 19 guidelines or updates, encompassing 31 drugs. The guidelines are widely cited, accessed, and downloaded, and are being used by leading external groups. Going forward, this resource will accomplish its goals via two specific aims. In Aim 1, CPIC will continue its work to select, create curate, and update CPIC guidelines (7-14/year) for all clinically actionable gene/drug groupings, and selectively expand the guidelines to include definitive clinical recommendations for non- actionable drugs linked to otherwise actionable genes. In Aim 2, CPIC will enhance access to and input into guidelines by external groups such as NIGMS's PGRN, NHGRI's Genomic Medicine Working group, AHRQ's www.guidelines.gov, NIH's Genetic Test Registry, PubMed, FDA, NHGRI's ClinGen, IOM's Genomic Medicine Roundtable, and professional societies by systematically evaluating community usage of CPIC guidelines on an ongoing basis to respond to the community and make enhancements as needed. Besides providing critical resources needed by the clinical pharmacogenomics community, CPIC guidelines provide proof of principle methods and processes that may be useful for other use cases in clinical implementation of genomic medicine.